Bulimia is a complex, disabling clinical disorder that remains poorly understood; reliably effective treatment methods have yet to be developed and evaluated. It is proposed here to compare two promising methods, using comprehensive assessment of psychological and physiological functioning, in the treatment of normal weight bulimics: cognitive restructuring (CR) with diet modification alone; and CR plus exposure and response prevention. Uncontrolled clinical reports have suggested the potential efficacy of both methods. The process mechanisms underlying these methods will be explored within the framework of a comparative treatment outcome study. A detailed monthly follow-up will provide data on the long-term effects of treatment (virtually non-existent in the current literature) and allow identification of the determinants of relapse when it occurs. Extensive assessment measures before, during, and after treatment will be the basis for investigating possible predictors of short-term and long-term therapeutic effects.